Stellaris 4.5.3 Experimental Branch Patch Notes - All Changes

A new version of the 4.5.3 branch is now on the stellaris_test branch on Steam, and it carries experimental changes. The update was posted on November 5, 2026 for Stellaris, and it covers a change to how computer-controlled empires handle resource stockpiles and the market, plus a major rework of how tooltips and modifiers in tooltips are handled.

The developers say both were risky enough that they didn't want to include them in 4.5.3 proper. They'd like more eyes on them before considering them for 4.6.0. We will go over every change in the 4.5.3 "Cygnus" experimental notes, from empire economies to the tooltip fixes.

Stellaris 4.5.3 Experimental Highlights

• Market behavior: computer-controlled empires now sell resources before a stockpile reaches its cap instead of wasting income.
• Tooltip rework: modifiers in tooltips are handled differently. Production and upkeep tooltips are not affected, since a different system handles them.
• Not an Open Beta: based on your feedback, the changes might be pushed or even cancelled.

If you want the stable release, see our 4.5.3 patch notes and the 4.5.3 Open Beta rundown.

4.5.3 Experimental Empire Behavior Changes

• Computer-controlled empires now sell resources on the market before a stockpile reaches its cap, instead of wasting income at the cap.
• Computer-controlled empires with a nearly full Trade stockpile now spend the surplus on resources they use, based on their real expenses. The developers note this is not currently as aggressive as it probably should be.
• Computer-controlled Nomad empires now trade on the market based on their Operational Reserves.
• Computer-controlled empires no longer spend currency on market purchases above their storage capacity.
• Computer-controlled empires no longer sell a strategic resource below their own minimum.
• Computer-controlled empires no longer skip market trades for weeks when their preferred resource cannot be bought or sold.
• Computer-controlled empires that exactly meet their pop or naval capacity goal now keep setting new goals, and Nomad computer-controlled empires with high fleet usage now apply all of their naval capacity plans.

4.5.3 Experimental UI and UX Changes

• Pop group upkeep and production tooltips on planets now show their modifiers instead of only the base value.
• Arkship tooltips no longer show placeholder labels or cut off parts of a modifier breakdown.
• The FTL windup tooltip now shows the megastructure bypass windup modifier from its real source.
• Static modifiers, for example from Ascension Perks, can now show a custom description with parameters.
• Modifier tooltips no longer repeat the same source several times. This includes happiness, growth, pop assembly, workforce, leader experience, shipyard, megastructure build speed, FTL windup, housing, amenities, stability and crime.
• Leader skill and job tooltips no longer show their name twice, for example "Governing Home Planet: Governing Home Planet: +5".
• The Empire Size tooltip no longer repeats the name of each source under its label.
• Breakdowns in the pop details tooltips now use the same indentation.
• The political power, empire size, housing and amenities tooltips of a pop group now show the base value for the whole group instead of for one pop.
• Triggered trait modifiers, for example from Aquatic, are now listed under the Species header, and a trait with several habitability modifiers now shows a single combined line.
• Traits added by auto-modding, for example Adaptive Cortex, are now listed under their own header in pop tooltips.
• The strata tooltip in the Jobs tab now shows the total housing and amenities usage of that strata on the planet.

4.5.3 Experimental Stability and Modding

• Fixed a possible crash when viewing the skill tooltip of an Arkship governor or a leader.
• Fixed small memory leaks from relics, ship sections and psionic auras at game load and on mod reload.
• A trait description with an exclusive trigger now replaces the other tooltip text, and only when its trigger is true.
• The print_modifiers console commands now show the modifiers of a pop group.

And that covers all of the changes in the Stellaris 4.5.3 experimental branch. You can read the official notes on the Steam news page, and let the team know what you think. For earlier updates, see our Dev Diary #439 rundown.